{"gene":"ADAM2","run_date":"2026-06-09T22:02:41","timeline":{"discoveries":[{"year":1995,"finding":"The disintegrin domain of mouse ADAM2 (mPH-30 beta) contains a QDE tripeptide (instead of RGD) in its cell recognition region; peptides containing this QDE sequence decrease sperm-egg binding and fusion by approximately 70%, indicating that the ADAM2 disintegrin domain participates in sperm-egg membrane interaction.","method":"Peptide inhibition assay, cDNA cloning and sequence analysis, sperm-egg binding/fusion bioassay","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional peptide inhibition assay with cloning, single lab but two orthogonal readouts (binding and fusion)","pmids":["7593287"],"is_preprint":false},{"year":1994,"finding":"A synthetic peptide corresponding to the putative fusion domain of ADAM2 alpha-subunit (PH-30 alpha residues 90-111) binds lipid membranes, undergoes a conformational transition to beta-structure upon membrane binding, and induces fusion of large unilamellar vesicles, supporting its role as a fusogenic peptide.","method":"Biophysical membrane assay (lipid mixing/vesicle fusion), circular dichroism, FTIR spectroscopy","journal":"Biochemistry","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with orthogonal biophysical methods; single lab","pmids":["8161498"],"is_preprint":false},{"year":1997,"finding":"The Pro-Pro sequence within the fusogenic region of PH-30 alpha (ADAM2 alpha subunit, residues 89-111) is critical for maintaining the beta-structure required for membrane fusogenic activity; replacement with Ala-Ala shifts to alpha-helical structure and reduces membrane fusion activity.","method":"Synthetic peptide analogs, CD spectroscopy, membrane-fusogenic activity assay","journal":"The journal of peptide research","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro mutagenesis analog approach with biophysical and functional validation; single lab","pmids":["9266484"],"is_preprint":false},{"year":2000,"finding":"Within the mouse ADAM2 disintegrin loop (QDECD sequence), the terminal aspartic acid residue is the critical functional amino acid for sperm-egg cell adhesion; substitutions at the terminal D dramatically reduce activity, while substitutions at the first D have virtually no effect.","method":"Site-directed mutagenesis of disintegrin loop, two independent cell adhesion/sperm-egg binding bioassays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — systematic point mutagenesis validated in two orthogonal functional bioassays in a single rigorous study","pmids":["10713078"],"is_preprint":false},{"year":2002,"finding":"The ADAM2 disintegrin domain binds to egg plasma membrane via MLDG-sensitive alpha4/alpha9 integrins (suggesting a role for this integrin subfamily as ADAM2 receptor); RGD-binding integrins contribute partially; anti-alpha6 antibody has little effect; CD9 antibody inhibits multivalent but not soluble ADAM2 binding.","method":"Peptide inhibition assay (MLDG, RGD), antibody blocking, two functional binding assays","journal":"Biology of reproduction","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple inhibitor approaches in two assays, single lab","pmids":["11906941"],"is_preprint":false},{"year":2004,"finding":"ADAM2 forms a protein complex with ADAM1a in testicular germ cells (the fertilin complex), and this complex is required for the appearance of ADAM3 (cyritestin) on the sperm surface; loss of ADAM1a results in loss of ADAM3 from sperm despite no direct interaction detected between the fertilin complex and ADAM3.","method":"ADAM1a knockout mouse, immunoblotting, surface protein analysis; co-immunoprecipitation (negative result for direct ADAM complex-ADAM3 interaction)","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic knockout with protein-level analysis, replicated across labs with consistent results","pmids":["15194697"],"is_preprint":false},{"year":2005,"finding":"In Adam2-null mice, ADAM3 (cyritestin) is synthesized at normal levels and acquires endoglycosidase H resistance (passes through Golgi) but fails to reach the cell surface, indicating ADAM2 is required for post-Golgi trafficking/sorting of ADAM3 to the sperm surface. ADAM2 and ADAM3 are found in a Triton X-100-insoluble (lipid raft-like) compartment on testicular sperm, and this insoluble compartment is disrupted in Adam2-knockout cells.","method":"Adam2 knockout mouse, subcellular fractionation, endoglycosidase H resistance assay, Triton X-100 solubility assay, immunoblotting","journal":"Biology of reproduction","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO with multiple biochemical fractionation methods definitively placing ADAM2 in secretory trafficking of ADAM3","pmids":["16014818"],"is_preprint":false},{"year":2006,"finding":"ADAM1b/ADAM2 fertilin complex on sperm is not required for sperm-egg fusion; ADAM1b-null sperm (which also lose surface ADAM2) can still fuse with zona pellucida-free eggs normally, indicating the primary role of ADAM1b/ADAM2 is in surface presentation of these proteins rather than in mediating fusion per se.","method":"ADAM1b knockout mouse, in vitro fertilization assay, sperm-egg fusion assay, immunoblotting","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO with direct functional assay and protein-level analysis; overturns prior model","pmids":["16407235"],"is_preprint":false},{"year":2007,"finding":"ADAM2 and ADAM3 form a protein complex on the surface of testicular germ cells and cauda epididymal sperm; the intracellular chaperone calnexin is a component of the testicular ADAM2-ADAM3 complex. In Adam2-null TGCs, surface ADAM3 shows increased endoglycosidase H-resistant forms suggesting instability, indicating ADAM2 association stabilizes ADAM3.","method":"Co-immunoprecipitation, surface protein labeling, endoglycosidase H resistance assay, Adam2 knockout mouse","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP identifying complex components with genetic KO validation and biochemical stability assay","pmids":["17439939"],"is_preprint":false},{"year":2008,"finding":"ADAM2 is expressed in migrating neuroblasts of the rostral migratory stream (RMS) and is required for their migration to the olfactory bulb; ADAM2 knockout mice show reduced olfactory bulb size, thinner rostral RMS, decreased neuroblast migration speed, and loss of directionality. A peptide mimicking the ADAM2 disintegrin loop phenocopies the KO, suggesting ADAM2 promotes migration through cell-cell interactions mediated by its disintegrin domain.","method":"ADAM2 knockout mouse, BrdU labeling in vivo, live slice imaging, RMS explant migration assay, disintegrin-loop peptide inhibition","journal":"The European journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO with multiple orthogonal migration assays (in vivo labeling, live imaging, explant) and peptide phenocopy","pmids":["18380661"],"is_preprint":false},{"year":2008,"finding":"Cyclic AMP (via membrane-permeable db-cAMP) causes a ~12-fold increase in lateral diffusion mobility of the ADAM1/ADAM2 (fertilin) complex within the guinea pig sperm plasma membrane, mimicking the mobilization observed during capacitation. This cAMP-induced mobilization is not observed in testicular sperm, indicating the responsiveness is acquired during epididymal maturation.","method":"FRAP (fluorescence redistribution after photobleaching), db-cAMP treatment, capacitation assays (hypermotility, acrosome reaction)","journal":"Biology of reproduction","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct FRAP measurement of protein mobility with pharmacological perturbation; single lab","pmids":["18667756"],"is_preprint":false},{"year":2009,"finding":"The cysteine-rich domain of Macaca fascicularis ADAM2 mediates protein-protein interactions, as demonstrated by Far-Western blot analysis, suggesting it contributes to formation of the fertilin complex.","method":"Far-Western blot, immunoblotting, subcellular fractionation","journal":"Animal reproduction science","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single Far-Western method in a single lab without reciprocal validation","pmids":["19443142"],"is_preprint":false},{"year":2009,"finding":"During in vitro capacitation, PCSK4-null sperm exhibit enhanced proteolytic processing of ADAM2 from a 46-kDa form to a 27-kDa form, and this processing is dependent on cholesterol efflux, linking membrane lipid changes during capacitation to ADAM2 proteolytic maturation.","method":"Comparative capacitation assay (PCSK4 KO vs wild-type sperm), immunoblotting, cholesterol efflux manipulation","journal":"Fertility and sterility","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO with defined biochemical outcome and mechanistic dissection (cholesterol dependence); single lab","pmids":["19342015"],"is_preprint":false},{"year":2010,"finding":"ADAM2 binds to mouse eggs via ITGB1-containing integrins; an anti-ITGB1 function-blocking antibody significantly inhibits ADAM2 binding. A novel integrin heterodimer ITGA9-ITGB7 (alpha9beta7) in RPMI 8866 cells functions as an ADAM2 binding partner, as demonstrated by anti-ITGA9 antibody and ITGB7 siRNA inhibition of cell adhesion to ADAM2.","method":"Antibody blocking, siRNA knockdown, cell adhesion assay, integrin expression analysis","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — antibody blocking and siRNA in two cell systems; single lab with orthogonal approaches","pmids":["21060781"],"is_preprint":false},{"year":2015,"finding":"The cytoplasmic domain of mouse ADAM2 may enable differential association with other ADAMs; monkey ADAM2 associates with chaperone proteins in testis; in humans, ADAM2 is expressed as a ~100 kDa protein in testis but is absent from sperm, unlike in mice and monkeys.","method":"Western blot with species-specific antibodies, co-immunoprecipitation (chaperone association)","journal":"PloS one","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single immunoblot and pulldown approach, limited mechanistic follow-up on domain function","pmids":["27341348"],"is_preprint":false},{"year":2023,"finding":"In mouse lung cancer models, ADAM2 functions as an oncogene that restrains interferon and TNF cytokine signaling, causing reduced presentation of tumor-associated antigens; ADAM2 also restricts expression of immune checkpoint molecules PDL1, LAG3, TIGIT, and TIM3 in the tumor microenvironment, as shown by loss- and gain-of-function CRISPR experiments.","method":"In vivo CRISPR/Cas9 screen, loss-of-function and gain-of-function experiments in mouse lung cancer models, cytokine signaling assays, antigen presentation assays","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo CRISPR with loss- and gain-of-function validation, single lab with multiple readouts","pmids":["37258521"],"is_preprint":false}],"current_model":"ADAM2 (fertilin beta) is a sperm-surface ADAM-family protein that forms heterodimeric complexes with ADAM1 isoforms in testicular germ cells; these complexes are required for post-Golgi trafficking and surface stabilization of ADAM3 via a lipid-raft-associated sorting platform, while ADAM2's own disintegrin domain (critical residue: terminal D of the ECD motif) mediates sperm-egg adhesion through alpha4/alpha9 integrins on the egg, its lateral membrane mobility is regulated by cAMP-dependent signaling during capacitation, it promotes neuroblast migration in the rostral migratory stream through disintegrin-domain-dependent cell-cell interactions, and in cancer contexts it restrains interferon/TNF cytokine signaling to modulate tumor antigen presentation and immune checkpoint expression."},"narrative":{"mechanistic_narrative":"ADAM2 (fertilin beta) is a sperm-surface ADAM-family protein whose principal characterized role is to assemble and chaperone the surface presentation of partner ADAM proteins on testicular germ cells and sperm [PMID:15194697, PMID:16014818]. ADAM2 forms a heterodimeric fertilin complex with ADAM1 isoforms (ADAM1a, ADAM1b) in testicular germ cells [PMID:15194697, PMID:16407235], and this complex—together with the chaperone calnexin—is required for post-Golgi trafficking and surface stabilization of ADAM3 (cyritestin): in Adam2-null sperm ADAM3 is synthesized and traverses the Golgi but fails to reach the surface, and ADAM2/ADAM3 partition into a Triton X-100-insoluble, lipid-raft-like compartment that collapses without ADAM2 [PMID:16014818, PMID:17439939]. The fertilin complex itself is dispensable for sperm-egg fusion, its primary function being surface presentation rather than the fusion step [PMID:16407235]. Independently, the ADAM2 disintegrin domain mediates cell-cell adhesion: its QDECD loop, and specifically the terminal aspartate, is the critical determinant for sperm-egg binding [PMID:7593287, PMID:10713078], engaging egg-surface alpha4/alpha9- and ITGB1-containing integrins [PMID:11906941, PMID:21060781]. This same disintegrin-loop activity drives neuroblast migration in the rostral migratory stream, where ADAM2 loss reduces migration speed and directionality and a disintegrin-loop peptide phenocopies the knockout [PMID:18380661]. ADAM2 membrane behavior is modulated during sperm maturation and capacitation: cAMP increases lateral diffusion of the fertilin complex in mature but not testicular sperm [PMID:18667756], and cholesterol efflux during capacitation drives proteolytic processing of ADAM2 [PMID:19342015]. In mouse lung cancer models ADAM2 acts as an oncogene that restrains interferon and TNF signaling, dampening tumor antigen presentation and immune checkpoint expression [PMID:37258521].","teleology":[{"year":1994,"claim":"Established that a defined region of the ADAM2 alpha-subunit can act as a fusogenic peptide, addressing whether fertilin contributes directly to membrane fusion machinery.","evidence":"Biophysical lipid-mixing and vesicle fusion assays with CD/FTIR on a synthetic PH-30 alpha peptide","pmids":["8161498"],"confidence":"Medium","gaps":["Activity shown only for an isolated synthetic peptide, not full-length protein in cellular context","Does not establish fusogenic role in vivo during fertilization"]},{"year":1995,"claim":"Identified the ADAM2 disintegrin domain as a participant in sperm-egg interaction, defining an adhesion function distinct from a canonical RGD integrin ligand.","evidence":"Peptide inhibition of sperm-egg binding/fusion using the QDE recognition sequence, with cDNA cloning","pmids":["7593287"],"confidence":"Medium","gaps":["Peptide inhibition does not identify the egg receptor","Magnitude of inhibition leaves residual binding unexplained"]},{"year":1997,"claim":"Refined the structural basis of fusogenic peptide activity by showing a Pro-Pro motif maintains the beta-structure required for fusion.","evidence":"CD spectroscopy and fusion assays on synthetic peptide analogs","pmids":["9266484"],"confidence":"Medium","gaps":["Structure-activity established only at peptide level","No demonstration that this region adopts the same conformation in intact ADAM2"]},{"year":2000,"claim":"Pinpointed the single critical residue (terminal aspartate of the QDECD loop) governing ADAM2 disintegrin adhesion, converting a domain-level model to residue-level resolution.","evidence":"Systematic site-directed mutagenesis of the disintegrin loop validated in two orthogonal sperm-egg/cell adhesion bioassays","pmids":["10713078"],"confidence":"High","gaps":["Does not identify the binding partner engaged by the loop","Adhesion contribution to overall fertilization efficiency not quantified"]},{"year":2002,"claim":"Identified candidate egg-surface receptors for the ADAM2 disintegrin domain, addressing what ADAM2 binds during gamete adhesion.","evidence":"MLDG/RGD peptide and anti-integrin/CD9 antibody blocking in two functional binding assays","pmids":["11906941"],"confidence":"Medium","gaps":["Inhibitor-based identification without direct biochemical receptor isolation","Relative contributions of alpha4/alpha9 vs RGD-binding integrins not resolved"]},{"year":2004,"claim":"Defined the fertilin complex (ADAM2-ADAM1a) and established that it is required for ADAM3 surface appearance, reframing ADAM2 as part of a surface-presentation pathway for other ADAMs.","evidence":"ADAM1a knockout mouse with surface protein analysis and co-immunoprecipitation","pmids":["15194697"],"confidence":"High","gaps":["No direct interaction detected between the fertilin complex and ADAM3, leaving the linkage mechanism unclear","Does not localize the step at which ADAM3 is lost"]},{"year":2005,"claim":"Localized ADAM2's role in ADAM3 biogenesis to post-Golgi trafficking and a lipid-raft-like compartment, distinguishing it from earlier secretory steps.","evidence":"Adam2 knockout mouse with endoglycosidase H resistance assay, Triton X-100 solubility fractionation, immunoblotting","pmids":["16014818"],"confidence":"High","gaps":["Molecular identity of the post-Golgi sorting machinery not defined","How ADAM2 directs ADAM3 to the surface mechanistically unresolved"]},{"year":2006,"claim":"Separated the fertilin complex's surface-presentation role from sperm-egg fusion, overturning the prior model that fertilin directly mediates fusion.","evidence":"ADAM1b knockout mouse with in vitro fertilization and zona-free fusion assays","pmids":["16407235"],"confidence":"High","gaps":["Does not exclude redundant fusion mediators compensating","Fertility consequences attributable specifically to ADAM2 not isolated here"]},{"year":2007,"claim":"Showed ADAM2 physically associates with and stabilizes ADAM3, with calnexin as a complex component, providing a biochemical basis for the trafficking dependence.","evidence":"Reciprocal co-immunoprecipitation, surface labeling, endoglycosidase H resistance, Adam2 knockout mouse","pmids":["17439939"],"confidence":"High","gaps":["Reconciliation with earlier negative ADAM3 interaction result not fully explained","Stoichiometry and architecture of the ADAM2-ADAM3-calnexin assembly unknown"]},{"year":2008,"claim":"Extended ADAM2 function beyond reproduction by demonstrating a disintegrin-domain-dependent role in neuroblast migration in the rostral migratory stream.","evidence":"ADAM2 knockout mouse with in vivo BrdU labeling, live slice imaging, explant migration assays, and disintegrin-loop peptide phenocopy","pmids":["18380661"],"confidence":"High","gaps":["The cell-surface partner mediating neuroblast cell-cell interaction not identified","Whether ADAM3/fertilin complex participates in neural context unknown"]},{"year":2008,"claim":"Demonstrated that fertilin complex lateral mobility is dynamically regulated by cAMP signaling, linking surface organization to capacitation-stage signaling.","evidence":"FRAP measurements with db-cAMP treatment in guinea pig sperm","pmids":["18667756"],"confidence":"Medium","gaps":["Downstream effectors connecting cAMP to mobility not defined","Functional consequence of increased mobility for fertilization not measured"]},{"year":2009,"claim":"Connected membrane lipid remodeling during capacitation to proteolytic maturation of ADAM2.","evidence":"Comparative capacitation assays in PCSK4-null vs wild-type sperm with cholesterol efflux manipulation and immunoblotting","pmids":["19342015"],"confidence":"Medium","gaps":["Protease directly responsible for the 46-to-27 kDa processing not identified","Functional role of the processed form unknown"]},{"year":2010,"claim":"Broadened the ADAM2 integrin receptor repertoire, identifying ITGB1-containing integrins and a novel ITGA9-ITGB7 heterodimer as binding partners.","evidence":"Antibody blocking and siRNA knockdown in cell adhesion assays across egg and RPMI 8866 cell systems","pmids":["21060781"],"confidence":"Medium","gaps":["Binding-partner identification relies on inhibition rather than direct complex isolation","Physiological relevance of ITGA9-ITGB7 outside the cell line untested"]},{"year":2016,"claim":"Highlighted species divergence in ADAM2 biology, showing human ADAM2 is testis-expressed but absent from sperm unlike mouse and monkey.","evidence":"Western blotting with species-specific antibodies and co-immunoprecipitation for chaperone association","pmids":["27341348"],"confidence":"Low","gaps":["Single immunoblot/pulldown approach without functional follow-up","Cytoplasmic-domain role in differential ADAM association only suggested, not demonstrated"]},{"year":2023,"claim":"Revealed an unexpected oncogenic, immunomodulatory role for ADAM2 in restraining cytokine signaling, antigen presentation, and checkpoint expression in tumors.","evidence":"In vivo CRISPR/Cas9 screen with loss- and gain-of-function experiments and cytokine/antigen-presentation readouts in mouse lung cancer models","pmids":["37258521"],"confidence":"Medium","gaps":["Molecular mechanism by which ADAM2 restrains interferon/TNF signaling not defined","Whether the disintegrin or other domains mediate this effect unknown","Relevance to human cancer untested"]},{"year":null,"claim":"How ADAM2's disintegrin-adhesion function, its fertilin-complex chaperone/trafficking role, and its tumor immunomodulatory activity mechanistically interrelate—and whether they share a common molecular activity—remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of the fertilin complex or its ADAM3 sorting platform","Direct molecular mechanism of the cancer immune phenotype undefined","Human ADAM2 function not characterized given its absence from sperm"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098631","term_label":"cell adhesion mediator activity","supporting_discovery_ids":[0,3,4,9,13]},{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[3,4,13]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[6,8,10]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[6]}],"pathway":[{"term_id":"R-HSA-1474165","term_label":"Reproduction","supporting_discovery_ids":[0,3,5,6,7]},{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[5,6,8]}],"complexes":["fertilin complex (ADAM1/ADAM2)","ADAM2-ADAM3-calnexin complex"],"partners":["ADAM1A","ADAM1B","ADAM3","CANX","ITGB1","ITGA9","ITGB7","ITGA4"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q99965","full_name":"Disintegrin and metalloproteinase domain-containing protein 2","aliases":["Cancer/testis antigen 15","CT15","Fertilin subunit beta","PH-30","PH30","PH30-beta"],"length_aa":735,"mass_kda":82.5,"function":"Sperm surface membrane protein that may be involved in sperm-egg plasma membrane adhesion and fusion during fertilization. Could have a direct role in sperm-zona binding or migration of sperm from the uterus into the oviduct. Interactions with egg membrane could be mediated via binding between its disintegrin-like domain to one or more integrins receptors on the egg. This is a non catalytic metalloprotease-like protein","subcellular_location":"Membrane","url":"https://www.uniprot.org/uniprotkb/Q99965/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ADAM2","classification":"Not Classified","n_dependent_lines":2,"n_total_lines":1208,"dependency_fraction":0.0016556291390728477},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/ADAM2","total_profiled":1310},"omim":[{"mim_id":"618602","title":"ADAM METALLOPEPTIDASE DOMAIN-CONTAINING PROTEIN 32; ADAM32","url":"https://www.omim.org/entry/618602"},{"mim_id":"605548","title":"A DISINTEGRIN AND METALLOPROTEINASE DOMAIN 15; ADAM15","url":"https://www.omim.org/entry/605548"},{"mim_id":"603713","title":"A DISINTEGRIN AND METALLOPROTEINASE DOMAIN 21; ADAM21","url":"https://www.omim.org/entry/603713"},{"mim_id":"603712","title":"A DISINTEGRIN AND METALLOPROTEINASE DOMAIN 20; ADAM20","url":"https://www.omim.org/entry/603712"},{"mim_id":"601858","title":"CALMEGIN; CLGN","url":"https://www.omim.org/entry/601858"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in single","driving_tissues":[{"tissue":"testis","ntpm":35.6}],"url":"https://www.proteinatlas.org/search/ADAM2"},"hgnc":{"alias_symbol":["PH-30b","PH30","CT15"],"prev_symbol":["FTNB"]},"alphafold":{"accession":"Q99965","domains":[{"cath_id":"3.40.390.10","chopping":"179-373","consensus_level":"medium","plddt":90.3919,"start":179,"end":373},{"cath_id":"-","chopping":"476-613","consensus_level":"high","plddt":94.2753,"start":476,"end":613},{"cath_id":"2.40.128","chopping":"26-144","consensus_level":"medium","plddt":85.2788,"start":26,"end":144}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q99965","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q99965-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q99965-F1-predicted_aligned_error_v6.png","plddt_mean":81.44},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ADAM2","jax_strain_url":"https://www.jax.org/strain/search?query=ADAM2"},"sequence":{"accession":"Q99965","fasta_url":"https://rest.uniprot.org/uniprotkb/Q99965.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q99965/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q99965"}},"corpus_meta":[{"pmid":"15194697","id":"PMC_15194697","title":"Possible function of the ADAM1a/ADAM2 Fertilin complex in the appearance of ADAM3 on the sperm surface.","date":"2004","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/15194697","citation_count":162,"is_preprint":false},{"pmid":"7593287","id":"PMC_7593287","title":"Mouse sperm-egg plasma membrane interactions: analysis of roles of egg integrins and the mouse sperm homologue of PH-30 (fertilin) beta.","date":"1995","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/7593287","citation_count":135,"is_preprint":false},{"pmid":"8161498","id":"PMC_8161498","title":"Membrane interaction and conformational properties of the putative fusion peptide of PH-30, a protein active in sperm-egg fusion.","date":"1994","source":"Biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/8161498","citation_count":84,"is_preprint":false},{"pmid":"16407235","id":"PMC_16407235","title":"Mouse sperm lacking ADAM1b/ADAM2 fertilin can fuse with the egg plasma membrane and effect fertilization.","date":"2006","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16407235","citation_count":69,"is_preprint":false},{"pmid":"10713078","id":"PMC_10713078","title":"Identification of key functional amino acids of the mouse fertilin beta (ADAM2) disintegrin loop for cell-cell adhesion during fertilization.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10713078","citation_count":64,"is_preprint":false},{"pmid":"11906941","id":"PMC_11906941","title":"Analysis of the roles of RGD-binding integrins, alpha(4)/alpha(9) integrins, alpha(6) integrins, and CD9 in the interaction of the fertilin beta (ADAM2) disintegrin domain with the mouse egg membrane.","date":"2002","source":"Biology of reproduction","url":"https://pubmed.ncbi.nlm.nih.gov/11906941","citation_count":61,"is_preprint":false},{"pmid":"2567502","id":"PMC_2567502","title":"Isolation and mapping of a polymorphic DNA sequence pH30 on chromosome 4[HGM provisional no. D4S139].","date":"1989","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/2567502","citation_count":60,"is_preprint":false},{"pmid":"17439939","id":"PMC_17439939","title":"Identification of an ADAM2-ADAM3 complex on the surface of mouse testicular germ cells and cauda epididymal sperm.","date":"2007","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17439939","citation_count":47,"is_preprint":false},{"pmid":"37258521","id":"PMC_37258521","title":"In vivo CRISPR screens reveal Serpinb9 and Adam2 as regulators of immune therapy response in lung cancer.","date":"2023","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/37258521","citation_count":36,"is_preprint":false},{"pmid":"16014818","id":"PMC_16014818","title":"Defects in secretory pathway trafficking during sperm development in Adam2 knockout mice.","date":"2005","source":"Biology of 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one","url":"https://pubmed.ncbi.nlm.nih.gov/26252478","citation_count":10,"is_preprint":false},{"pmid":"30396079","id":"PMC_30396079","title":"Effects of ADAM2 silencing on isoflurane-induced cognitive dysfunction via the P13K/Akt signaling pathway in immature rats.","date":"2018","source":"Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie","url":"https://pubmed.ncbi.nlm.nih.gov/30396079","citation_count":10,"is_preprint":false},{"pmid":"19443142","id":"PMC_19443142","title":"Processing and subcellular localization of ADAM2 in the Macaca fascicularis testis and sperm.","date":"2009","source":"Animal reproduction science","url":"https://pubmed.ncbi.nlm.nih.gov/19443142","citation_count":9,"is_preprint":false},{"pmid":"19342015","id":"PMC_19342015","title":"PCSK4-null sperm display enhanced protein tyrosine phosphorylation and ADAM2 proteolytic processing during in vitro capacitation.","date":"2009","source":"Fertility and sterility","url":"https://pubmed.ncbi.nlm.nih.gov/19342015","citation_count":9,"is_preprint":false},{"pmid":"30463455","id":"PMC_30463455","title":"Assessing the potential of HSPA2 and ADAM2 as two biomarkers for human sperm selection.","date":"2018","source":"Human fertility (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/30463455","citation_count":7,"is_preprint":false},{"pmid":"18667756","id":"PMC_18667756","title":"Cyclic 3',5'-AMP causes ADAM1/ADAM2 to rapidly diffuse within the plasma membrane of guinea pig sperm.","date":"2008","source":"Biology of reproduction","url":"https://pubmed.ncbi.nlm.nih.gov/18667756","citation_count":6,"is_preprint":false},{"pmid":"14510675","id":"PMC_14510675","title":"Chromosomal mapping, sequence and transcription analysis of the porcine fertilin beta gene (ADAM2).","date":"2003","source":"Animal genetics","url":"https://pubmed.ncbi.nlm.nih.gov/14510675","citation_count":4,"is_preprint":false},{"pmid":"33936295","id":"PMC_33936295","title":"Localization and expression of ADAM2 in the dromedary camel testis, epididymis and sperm during rutting season.","date":"2021","source":"Animal reproduction","url":"https://pubmed.ncbi.nlm.nih.gov/33936295","citation_count":2,"is_preprint":false},{"pmid":"39928278","id":"PMC_39928278","title":"Exploring miR-34a, miR-449, and ADAM2/ADAM7 Expressions as Potential Biomarkers in Male Infertility: A Combined In Silico and Experimental Approach.","date":"2025","source":"Biochemical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/39928278","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":13547,"output_tokens":3786,"usd":0.048716,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11689,"output_tokens":4609,"usd":0.086835,"stage2_stop_reason":"end_turn"},"total_usd":0.135551,"stage1_batch_id":"msgbatch_0179Z2pxRYBsXi2xADneafRw","stage2_batch_id":"msgbatch_01LaY9ZaVdgjWArcZo9eqQE5","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1995,\n      \"finding\": \"The disintegrin domain of mouse ADAM2 (mPH-30 beta) contains a QDE tripeptide (instead of RGD) in its cell recognition region; peptides containing this QDE sequence decrease sperm-egg binding and fusion by approximately 70%, indicating that the ADAM2 disintegrin domain participates in sperm-egg membrane interaction.\",\n      \"method\": \"Peptide inhibition assay, cDNA cloning and sequence analysis, sperm-egg binding/fusion bioassay\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional peptide inhibition assay with cloning, single lab but two orthogonal readouts (binding and fusion)\",\n      \"pmids\": [\"7593287\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"A synthetic peptide corresponding to the putative fusion domain of ADAM2 alpha-subunit (PH-30 alpha residues 90-111) binds lipid membranes, undergoes a conformational transition to beta-structure upon membrane binding, and induces fusion of large unilamellar vesicles, supporting its role as a fusogenic peptide.\",\n      \"method\": \"Biophysical membrane assay (lipid mixing/vesicle fusion), circular dichroism, FTIR spectroscopy\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with orthogonal biophysical methods; single lab\",\n      \"pmids\": [\"8161498\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"The Pro-Pro sequence within the fusogenic region of PH-30 alpha (ADAM2 alpha subunit, residues 89-111) is critical for maintaining the beta-structure required for membrane fusogenic activity; replacement with Ala-Ala shifts to alpha-helical structure and reduces membrane fusion activity.\",\n      \"method\": \"Synthetic peptide analogs, CD spectroscopy, membrane-fusogenic activity assay\",\n      \"journal\": \"The journal of peptide research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro mutagenesis analog approach with biophysical and functional validation; single lab\",\n      \"pmids\": [\"9266484\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Within the mouse ADAM2 disintegrin loop (QDECD sequence), the terminal aspartic acid residue is the critical functional amino acid for sperm-egg cell adhesion; substitutions at the terminal D dramatically reduce activity, while substitutions at the first D have virtually no effect.\",\n      \"method\": \"Site-directed mutagenesis of disintegrin loop, two independent cell adhesion/sperm-egg binding bioassays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — systematic point mutagenesis validated in two orthogonal functional bioassays in a single rigorous study\",\n      \"pmids\": [\"10713078\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"The ADAM2 disintegrin domain binds to egg plasma membrane via MLDG-sensitive alpha4/alpha9 integrins (suggesting a role for this integrin subfamily as ADAM2 receptor); RGD-binding integrins contribute partially; anti-alpha6 antibody has little effect; CD9 antibody inhibits multivalent but not soluble ADAM2 binding.\",\n      \"method\": \"Peptide inhibition assay (MLDG, RGD), antibody blocking, two functional binding assays\",\n      \"journal\": \"Biology of reproduction\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple inhibitor approaches in two assays, single lab\",\n      \"pmids\": [\"11906941\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"ADAM2 forms a protein complex with ADAM1a in testicular germ cells (the fertilin complex), and this complex is required for the appearance of ADAM3 (cyritestin) on the sperm surface; loss of ADAM1a results in loss of ADAM3 from sperm despite no direct interaction detected between the fertilin complex and ADAM3.\",\n      \"method\": \"ADAM1a knockout mouse, immunoblotting, surface protein analysis; co-immunoprecipitation (negative result for direct ADAM complex-ADAM3 interaction)\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic knockout with protein-level analysis, replicated across labs with consistent results\",\n      \"pmids\": [\"15194697\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"In Adam2-null mice, ADAM3 (cyritestin) is synthesized at normal levels and acquires endoglycosidase H resistance (passes through Golgi) but fails to reach the cell surface, indicating ADAM2 is required for post-Golgi trafficking/sorting of ADAM3 to the sperm surface. ADAM2 and ADAM3 are found in a Triton X-100-insoluble (lipid raft-like) compartment on testicular sperm, and this insoluble compartment is disrupted in Adam2-knockout cells.\",\n      \"method\": \"Adam2 knockout mouse, subcellular fractionation, endoglycosidase H resistance assay, Triton X-100 solubility assay, immunoblotting\",\n      \"journal\": \"Biology of reproduction\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO with multiple biochemical fractionation methods definitively placing ADAM2 in secretory trafficking of ADAM3\",\n      \"pmids\": [\"16014818\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"ADAM1b/ADAM2 fertilin complex on sperm is not required for sperm-egg fusion; ADAM1b-null sperm (which also lose surface ADAM2) can still fuse with zona pellucida-free eggs normally, indicating the primary role of ADAM1b/ADAM2 is in surface presentation of these proteins rather than in mediating fusion per se.\",\n      \"method\": \"ADAM1b knockout mouse, in vitro fertilization assay, sperm-egg fusion assay, immunoblotting\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO with direct functional assay and protein-level analysis; overturns prior model\",\n      \"pmids\": [\"16407235\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"ADAM2 and ADAM3 form a protein complex on the surface of testicular germ cells and cauda epididymal sperm; the intracellular chaperone calnexin is a component of the testicular ADAM2-ADAM3 complex. In Adam2-null TGCs, surface ADAM3 shows increased endoglycosidase H-resistant forms suggesting instability, indicating ADAM2 association stabilizes ADAM3.\",\n      \"method\": \"Co-immunoprecipitation, surface protein labeling, endoglycosidase H resistance assay, Adam2 knockout mouse\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP identifying complex components with genetic KO validation and biochemical stability assay\",\n      \"pmids\": [\"17439939\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"ADAM2 is expressed in migrating neuroblasts of the rostral migratory stream (RMS) and is required for their migration to the olfactory bulb; ADAM2 knockout mice show reduced olfactory bulb size, thinner rostral RMS, decreased neuroblast migration speed, and loss of directionality. A peptide mimicking the ADAM2 disintegrin loop phenocopies the KO, suggesting ADAM2 promotes migration through cell-cell interactions mediated by its disintegrin domain.\",\n      \"method\": \"ADAM2 knockout mouse, BrdU labeling in vivo, live slice imaging, RMS explant migration assay, disintegrin-loop peptide inhibition\",\n      \"journal\": \"The European journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO with multiple orthogonal migration assays (in vivo labeling, live imaging, explant) and peptide phenocopy\",\n      \"pmids\": [\"18380661\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Cyclic AMP (via membrane-permeable db-cAMP) causes a ~12-fold increase in lateral diffusion mobility of the ADAM1/ADAM2 (fertilin) complex within the guinea pig sperm plasma membrane, mimicking the mobilization observed during capacitation. This cAMP-induced mobilization is not observed in testicular sperm, indicating the responsiveness is acquired during epididymal maturation.\",\n      \"method\": \"FRAP (fluorescence redistribution after photobleaching), db-cAMP treatment, capacitation assays (hypermotility, acrosome reaction)\",\n      \"journal\": \"Biology of reproduction\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct FRAP measurement of protein mobility with pharmacological perturbation; single lab\",\n      \"pmids\": [\"18667756\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"The cysteine-rich domain of Macaca fascicularis ADAM2 mediates protein-protein interactions, as demonstrated by Far-Western blot analysis, suggesting it contributes to formation of the fertilin complex.\",\n      \"method\": \"Far-Western blot, immunoblotting, subcellular fractionation\",\n      \"journal\": \"Animal reproduction science\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Far-Western method in a single lab without reciprocal validation\",\n      \"pmids\": [\"19443142\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"During in vitro capacitation, PCSK4-null sperm exhibit enhanced proteolytic processing of ADAM2 from a 46-kDa form to a 27-kDa form, and this processing is dependent on cholesterol efflux, linking membrane lipid changes during capacitation to ADAM2 proteolytic maturation.\",\n      \"method\": \"Comparative capacitation assay (PCSK4 KO vs wild-type sperm), immunoblotting, cholesterol efflux manipulation\",\n      \"journal\": \"Fertility and sterility\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO with defined biochemical outcome and mechanistic dissection (cholesterol dependence); single lab\",\n      \"pmids\": [\"19342015\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"ADAM2 binds to mouse eggs via ITGB1-containing integrins; an anti-ITGB1 function-blocking antibody significantly inhibits ADAM2 binding. A novel integrin heterodimer ITGA9-ITGB7 (alpha9beta7) in RPMI 8866 cells functions as an ADAM2 binding partner, as demonstrated by anti-ITGA9 antibody and ITGB7 siRNA inhibition of cell adhesion to ADAM2.\",\n      \"method\": \"Antibody blocking, siRNA knockdown, cell adhesion assay, integrin expression analysis\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — antibody blocking and siRNA in two cell systems; single lab with orthogonal approaches\",\n      \"pmids\": [\"21060781\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"The cytoplasmic domain of mouse ADAM2 may enable differential association with other ADAMs; monkey ADAM2 associates with chaperone proteins in testis; in humans, ADAM2 is expressed as a ~100 kDa protein in testis but is absent from sperm, unlike in mice and monkeys.\",\n      \"method\": \"Western blot with species-specific antibodies, co-immunoprecipitation (chaperone association)\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single immunoblot and pulldown approach, limited mechanistic follow-up on domain function\",\n      \"pmids\": [\"27341348\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"In mouse lung cancer models, ADAM2 functions as an oncogene that restrains interferon and TNF cytokine signaling, causing reduced presentation of tumor-associated antigens; ADAM2 also restricts expression of immune checkpoint molecules PDL1, LAG3, TIGIT, and TIM3 in the tumor microenvironment, as shown by loss- and gain-of-function CRISPR experiments.\",\n      \"method\": \"In vivo CRISPR/Cas9 screen, loss-of-function and gain-of-function experiments in mouse lung cancer models, cytokine signaling assays, antigen presentation assays\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo CRISPR with loss- and gain-of-function validation, single lab with multiple readouts\",\n      \"pmids\": [\"37258521\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ADAM2 (fertilin beta) is a sperm-surface ADAM-family protein that forms heterodimeric complexes with ADAM1 isoforms in testicular germ cells; these complexes are required for post-Golgi trafficking and surface stabilization of ADAM3 via a lipid-raft-associated sorting platform, while ADAM2's own disintegrin domain (critical residue: terminal D of the ECD motif) mediates sperm-egg adhesion through alpha4/alpha9 integrins on the egg, its lateral membrane mobility is regulated by cAMP-dependent signaling during capacitation, it promotes neuroblast migration in the rostral migratory stream through disintegrin-domain-dependent cell-cell interactions, and in cancer contexts it restrains interferon/TNF cytokine signaling to modulate tumor antigen presentation and immune checkpoint expression.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"ADAM2 (fertilin beta) is a sperm-surface ADAM-family protein whose principal characterized role is to assemble and chaperone the surface presentation of partner ADAM proteins on testicular germ cells and sperm [#5, #6]. ADAM2 forms a heterodimeric fertilin complex with ADAM1 isoforms (ADAM1a, ADAM1b) in testicular germ cells [#5, #7], and this complex—together with the chaperone calnexin—is required for post-Golgi trafficking and surface stabilization of ADAM3 (cyritestin): in Adam2-null sperm ADAM3 is synthesized and traverses the Golgi but fails to reach the surface, and ADAM2/ADAM3 partition into a Triton X-100-insoluble, lipid-raft-like compartment that collapses without ADAM2 [#6, #8]. The fertilin complex itself is dispensable for sperm-egg fusion, its primary function being surface presentation rather than the fusion step [#7]. Independently, the ADAM2 disintegrin domain mediates cell-cell adhesion: its QDECD loop, and specifically the terminal aspartate, is the critical determinant for sperm-egg binding [#0, #3], engaging egg-surface alpha4/alpha9- and ITGB1-containing integrins [#4, #13]. This same disintegrin-loop activity drives neuroblast migration in the rostral migratory stream, where ADAM2 loss reduces migration speed and directionality and a disintegrin-loop peptide phenocopies the knockout [#9]. ADAM2 membrane behavior is modulated during sperm maturation and capacitation: cAMP increases lateral diffusion of the fertilin complex in mature but not testicular sperm [#10], and cholesterol efflux during capacitation drives proteolytic processing of ADAM2 [#12]. In mouse lung cancer models ADAM2 acts as an oncogene that restrains interferon and TNF signaling, dampening tumor antigen presentation and immune checkpoint expression [#15].\",\n  \"teleology\": [\n    {\n      \"year\": 1994,\n      \"claim\": \"Established that a defined region of the ADAM2 alpha-subunit can act as a fusogenic peptide, addressing whether fertilin contributes directly to membrane fusion machinery.\",\n      \"evidence\": \"Biophysical lipid-mixing and vesicle fusion assays with CD/FTIR on a synthetic PH-30 alpha peptide\",\n      \"pmids\": [\"8161498\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Activity shown only for an isolated synthetic peptide, not full-length protein in cellular context\", \"Does not establish fusogenic role in vivo during fertilization\"]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"Identified the ADAM2 disintegrin domain as a participant in sperm-egg interaction, defining an adhesion function distinct from a canonical RGD integrin ligand.\",\n      \"evidence\": \"Peptide inhibition of sperm-egg binding/fusion using the QDE recognition sequence, with cDNA cloning\",\n      \"pmids\": [\"7593287\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Peptide inhibition does not identify the egg receptor\", \"Magnitude of inhibition leaves residual binding unexplained\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Refined the structural basis of fusogenic peptide activity by showing a Pro-Pro motif maintains the beta-structure required for fusion.\",\n      \"evidence\": \"CD spectroscopy and fusion assays on synthetic peptide analogs\",\n      \"pmids\": [\"9266484\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structure-activity established only at peptide level\", \"No demonstration that this region adopts the same conformation in intact ADAM2\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Pinpointed the single critical residue (terminal aspartate of the QDECD loop) governing ADAM2 disintegrin adhesion, converting a domain-level model to residue-level resolution.\",\n      \"evidence\": \"Systematic site-directed mutagenesis of the disintegrin loop validated in two orthogonal sperm-egg/cell adhesion bioassays\",\n      \"pmids\": [\"10713078\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not identify the binding partner engaged by the loop\", \"Adhesion contribution to overall fertilization efficiency not quantified\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Identified candidate egg-surface receptors for the ADAM2 disintegrin domain, addressing what ADAM2 binds during gamete adhesion.\",\n      \"evidence\": \"MLDG/RGD peptide and anti-integrin/CD9 antibody blocking in two functional binding assays\",\n      \"pmids\": [\"11906941\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Inhibitor-based identification without direct biochemical receptor isolation\", \"Relative contributions of alpha4/alpha9 vs RGD-binding integrins not resolved\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Defined the fertilin complex (ADAM2-ADAM1a) and established that it is required for ADAM3 surface appearance, reframing ADAM2 as part of a surface-presentation pathway for other ADAMs.\",\n      \"evidence\": \"ADAM1a knockout mouse with surface protein analysis and co-immunoprecipitation\",\n      \"pmids\": [\"15194697\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No direct interaction detected between the fertilin complex and ADAM3, leaving the linkage mechanism unclear\", \"Does not localize the step at which ADAM3 is lost\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Localized ADAM2's role in ADAM3 biogenesis to post-Golgi trafficking and a lipid-raft-like compartment, distinguishing it from earlier secretory steps.\",\n      \"evidence\": \"Adam2 knockout mouse with endoglycosidase H resistance assay, Triton X-100 solubility fractionation, immunoblotting\",\n      \"pmids\": [\"16014818\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular identity of the post-Golgi sorting machinery not defined\", \"How ADAM2 directs ADAM3 to the surface mechanistically unresolved\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Separated the fertilin complex's surface-presentation role from sperm-egg fusion, overturning the prior model that fertilin directly mediates fusion.\",\n      \"evidence\": \"ADAM1b knockout mouse with in vitro fertilization and zona-free fusion assays\",\n      \"pmids\": [\"16407235\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not exclude redundant fusion mediators compensating\", \"Fertility consequences attributable specifically to ADAM2 not isolated here\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Showed ADAM2 physically associates with and stabilizes ADAM3, with calnexin as a complex component, providing a biochemical basis for the trafficking dependence.\",\n      \"evidence\": \"Reciprocal co-immunoprecipitation, surface labeling, endoglycosidase H resistance, Adam2 knockout mouse\",\n      \"pmids\": [\"17439939\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Reconciliation with earlier negative ADAM3 interaction result not fully explained\", \"Stoichiometry and architecture of the ADAM2-ADAM3-calnexin assembly unknown\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Extended ADAM2 function beyond reproduction by demonstrating a disintegrin-domain-dependent role in neuroblast migration in the rostral migratory stream.\",\n      \"evidence\": \"ADAM2 knockout mouse with in vivo BrdU labeling, live slice imaging, explant migration assays, and disintegrin-loop peptide phenocopy\",\n      \"pmids\": [\"18380661\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"The cell-surface partner mediating neuroblast cell-cell interaction not identified\", \"Whether ADAM3/fertilin complex participates in neural context unknown\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Demonstrated that fertilin complex lateral mobility is dynamically regulated by cAMP signaling, linking surface organization to capacitation-stage signaling.\",\n      \"evidence\": \"FRAP measurements with db-cAMP treatment in guinea pig sperm\",\n      \"pmids\": [\"18667756\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Downstream effectors connecting cAMP to mobility not defined\", \"Functional consequence of increased mobility for fertilization not measured\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Connected membrane lipid remodeling during capacitation to proteolytic maturation of ADAM2.\",\n      \"evidence\": \"Comparative capacitation assays in PCSK4-null vs wild-type sperm with cholesterol efflux manipulation and immunoblotting\",\n      \"pmids\": [\"19342015\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Protease directly responsible for the 46-to-27 kDa processing not identified\", \"Functional role of the processed form unknown\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Broadened the ADAM2 integrin receptor repertoire, identifying ITGB1-containing integrins and a novel ITGA9-ITGB7 heterodimer as binding partners.\",\n      \"evidence\": \"Antibody blocking and siRNA knockdown in cell adhesion assays across egg and RPMI 8866 cell systems\",\n      \"pmids\": [\"21060781\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Binding-partner identification relies on inhibition rather than direct complex isolation\", \"Physiological relevance of ITGA9-ITGB7 outside the cell line untested\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Highlighted species divergence in ADAM2 biology, showing human ADAM2 is testis-expressed but absent from sperm unlike mouse and monkey.\",\n      \"evidence\": \"Western blotting with species-specific antibodies and co-immunoprecipitation for chaperone association\",\n      \"pmids\": [\"27341348\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single immunoblot/pulldown approach without functional follow-up\", \"Cytoplasmic-domain role in differential ADAM association only suggested, not demonstrated\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Revealed an unexpected oncogenic, immunomodulatory role for ADAM2 in restraining cytokine signaling, antigen presentation, and checkpoint expression in tumors.\",\n      \"evidence\": \"In vivo CRISPR/Cas9 screen with loss- and gain-of-function experiments and cytokine/antigen-presentation readouts in mouse lung cancer models\",\n      \"pmids\": [\"37258521\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular mechanism by which ADAM2 restrains interferon/TNF signaling not defined\", \"Whether the disintegrin or other domains mediate this effect unknown\", \"Relevance to human cancer untested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How ADAM2's disintegrin-adhesion function, its fertilin-complex chaperone/trafficking role, and its tumor immunomodulatory activity mechanistically interrelate—and whether they share a common molecular activity—remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of the fertilin complex or its ADAM3 sorting platform\", \"Direct molecular mechanism of the cancer immune phenotype undefined\", \"Human ADAM2 function not characterized given its absence from sperm\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098631\", \"supporting_discovery_ids\": [0, 3, 4, 9, 13]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [3, 4, 13]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [6, 8, 10]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [6]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1474165\", \"supporting_discovery_ids\": [0, 3, 5, 6, 7]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [5, 6, 8]}\n    ],\n    \"complexes\": [\"fertilin complex (ADAM1/ADAM2)\", \"ADAM2-ADAM3-calnexin complex\"],\n    \"partners\": [\"ADAM1A\", \"ADAM1B\", \"ADAM3\", \"CANX\", \"ITGB1\", \"ITGA9\", \"ITGB7\", \"ITGA4\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}